Fertilizer helps plants to thrive by adjusting the soil nutrients. It’s important to buy the right fertilizer so that you get the best possible results! Garden fertilizers tend to contain nitrogen, phosphorus, and potassium, which are the 3 most important nutrients for plant growth. Evaluate your garden before you look for fertilizer by considering the soil nutrients and the type of plants you have. Then visit your local garden center and purchase fertilizer based on the nutrients ratio and the type of results you're aiming for.

Use a soil test kit to determine the nutrients the soil needs. Take a sample of the soil and place it into the testing chamber of your soil test kit. Add the required amount of distilled water and then check the color result against the color chart to determine the levels of nitrogen, phosphorus, and potassium. Read the label of the soil test kit carefully to interpret the results.[1]

You can purchase soil test kits from garden centers.

This is the best and most accurate way to pick the right fertilizer for your garden.

Can you please put wikiHow on the whitelist for your ad blocker? wikiHow relies on ad money to give you our free how-to guides. Learn how.

Check the type of plants that you’re fertilizing the soil for. Another very important part of buying the right fertilizer is choosing one specifically for the particular plants that you’re growing. Determine if the fertilizer is going to be used for fruits, vegetables, lawns, flowers, or any other type of plant. If you’re wanting to use the fertilizer for multiple different plants, an all-purpose type will do the trick.[2]

Try to get as specific as possible when determining what type of plants. For example, you can buy fertilizer specifically for citrus trees, roses, or native plants just to name a few.

Measure your garden to calculate the amount of fertilizer you need. Get a measuring tape and take the appropriate measurements to calculate the area of your garden. Write the measurement down so that you don’t forget it and bring it along with you when you purchase the fertilizer. Read the label on the fertilizer carefully to check how much you’ll need based on the size of your garden.[3]

For rectangular shapes, find the area by multiplying the width by the length.

For triangular gardens, calculate the area by multiplying the height by ½ of the base.

For circular gardens, multiply the radius squared by π to calculate the area.

Select a fertilizer based on the NPK ratio on the label. All commercial fertilizers are labeled with three numbers that help you to make the right choice for your garden. The numbers represent the percentage of nitrogen, phosphate (which is representative of phosphorus), and potash (which indicates potassium) in the fertilizer. Choose a fertilizer that provides higher amounts of the nutrient that your soil is lacking.[5]

This means that a NPK value 3-1-2 indicates 3 parts nitrogen to 1 part phosphorus to 2 parts potassium. Pick this type of fertilizer if the soil needs a lot of nitrogen.

Don’t worry if you haven’t done a soil test to check exactly what nutrients the soil needs. Generally, the label on the fertilizer will specify the type of plants and soil that the fertilizer is recommended for.

Lawn fertilizers tend to have higher amounts of nitrogen whereas fertilizers designed for fruit and flowers have higher levels of potassium and phosphorus.[6]

General purpose fertilizers often have an equal ratio of the nutrients.

Choose granular fertilizer if you’re aiming for longevity. Granular fertilizer is the most popular type of fertilizer due to it being easy to use and long-lasting. Pick this type of fertilizer if you’re wanting a fertilizer that you simply spread straight out of the bag using a fertilizer spreader, with no special preparation required.[7]

Granular fertilizer comes in either fast or slow-release granules. Fast-release fertilizer tends to be cheaper and more effective in cold weather, while slow-release fertilizer is more efficient in the long-run but slightly more expensive.

Pick liquid fertilizer if you want to see very fast results. Liquid fertilizer is a good choice if you don’t want to carry a heavy bag of fertilizer around your garden! Simply attach the concentrated liquid fertilizer to the hose and a spray nozzle and then aim the liquid at your garden as you hold down the trigger. Although liquid fertilizer has very quick results, it doesn’t last as long as granular fertilizer and it needs to be repeated more frequently.[8]

Choose synthetic fertilizer for an immediate release of nutrients into the soil. Synthetic fertilizer is chemically manufactured and it tends to have quick, visible results. Pick a synthetic fertilizer if you are aiming for immediate improvements, rather than slower, long-term results.[9]

Pick organic fertilizer if you don’t mind waiting to see longer-lasting results. Organic fertilizer is great if you have time and patience to watch your garden flourish. Compost, manure, and seaweed are common types of organic fertilizer. Methods of spreading organic fertilizer include by hand, with a fertilizer spreader, or with a rake.[10]

Bat guano and feather meal have high levels of nitrogen, while bone meal and shrimp waste are particularly high in phosphorous. If you're wanting an organic fertilizer that's high in potassium, choose kelp or wood ashes.[11]

Organic fertilizers tend to be slow-releasing, which means that they slowly release nitrogen into the soil rather than working straight away.

A disadvantage of some organic fertilizers is that there can be an unpleasant smell.

Warning: If you have a stream or waterway close by, pick a slow-release organic fertilizer. This minimizes the risk of runoff, which causes excessive nutrients accumulating in the waterway. This process is called eutrophication and it can unbalance the natural ecosystem and result in serious damage.[12]

Advertisement

Community Q&A

Tips

Choose a fertilizer based on the type of plants in your garden and the nutrients that the soil needs. The climate and environmental surroundings don't play a role in determining the best fertilizer for your garden.